Insights into the antibacterial and immunomodulatory functions of tilapia hepcidin (TH)2-3 against Vibrio vulnificus infection in mice.

The antimicrobial and immunomodulatory functions of the antimicrobial peptide, tilapia hepcidin (TH)2-3, against a bacterial endotoxin under in vitro conditions was previously reported. In this study, we investigated the antibacterial and immunomodulatory functions of TH2-3 in mice infected with the pathogen, Vibrio vulnificus. A TH2-3 injection in V. vulnificus-infected mice produced an increased survival rate compared to mice injected with V. vulnificus only. In addition, a TH2-3 injection increased the bacteriostatic property against V. vulnificus in mice. Gene expressions examined using a microarray demonstrated that TH2-3 modulated several V. vulnificus-responsive genes in the host. A neutralizing antibody assay of mice serum against inactivated V. vulnificus antigen-coated plates demonstrated the induction of an immune response by TH2-3 against the pathogen. Taken together, TH2-3 enhanced the survival rate of mice against the bacterial pathogen V. vulnificus through both antimicrobial and immunomodulatory functions. These properties make the TH2-3 peptide a good candidate for development as a new antimicrobial drug and suggest that TH2-3 can underpin the design of adjuvants for further development of vaccines.